Sulfurized nitrated alkylphenol salts and lubricant compositions thereof

ABSTRACT

A multipurpose additive for lubricating oils of antioxidant, antithickening, anticorrosion and detergent properties comprising a sulfurized Group II metal nitrated alkylphenolate prepared by (1) contacting an alkylphenol with a nitrating agent to form nitrated alkylphenol, (2) treating the nitrated alkylphenol with a Group II metal oxide, hydroxide or alkoxyalkoxide to form the Group II metal salt of nitrated alkylphenol, (3) treating the Group II metal salt with sulfur to form the sulfurized reaction product of the Group II metal salt of a nitrated alkylphenol.

United States Patent [1 1 Chafetz et a1.

[451 July 29,1975

1 1 SULFURIZED NITRATED ALKYLPHENOL SALTS AND LUBRICANT COMPOSITIONS THEREOF [75] Inventors: Harry Chafetz, Poughkeepsie;

Rodney L. Sung, Fishkill, both of NY.

[73] Assignee: Texaco Inc., New York, NY.

[22] Filed: Dec. 21, 1973 [21] Appl. No.: 427,154

3,549,534 12/1970 Holstedt et a1. 252/42.7

3,595,791 7/1971 Cohen 252/42.7 X 3,706,632 12/1972 Day et a1. 252/42.7

[57] ABSTRACT A multipurpose additive for lubricating oils of antioxidant, antithickening, anticorrosion and detergent properties comprising a sulfurized Group 11 metal nitrated alkylphenolate prepared by (1) contacting an alkylphenol with a nitrating agent to form nitrated alkylphenol, (2) treating the nitrated alkylphenol with a Group 11 metal oxide, hydroxide or alkoxyalkoxide to form the Group 11 metal salt of nitrated alkylphenol, (3) treating the Group 11 metal salt with sulfur to form the sulfurized reaction product of the Group 11 metal salt of a nitrated alkylphenol.

7 Claims, No Drawings SULFURIZED NITRATED ALKYLPHENOL SALTS AND LUBRICANT COMPOSITIONS THEREOF BACKGROUND OF INVENTION It is well known that lubricating oils tend to deteriorate under the conditions of use in present day diesel and automative engines with attendant formation of sludge, lacquer and resinous materials which adhere to the engine parts, particularly the engine rings. grooves and skirts. Further, the deterioration of the oils and some of the additives commonly found therein promote undesirable thickening of said oils and the production of corrosive bodies which attack the enclosing metal surfaces.

One class of compounds which are effective in lubricating oils, particularly diesel oils are the normal and overbased sulfurized calcium alkylphenolates such as described in US. Pat. Nos. 3,474,035 3,528,917 and 3,706,632. These materials not only function as effective detergent dispersant properties but also contain antioxidant properties which renders them anticorrosive, antithickening agents, that is, a multipurpose additive, Although these prior additives are superior in respect to their alternative known multipurpose lube oil additives. the increasing severity of conditions placed on lubricating oils and particularly diesel lubricating oils via antipollution devices and techniques associated with the automotive and diesel engines requires a continuing search for multipurpose detergent dispersant additives which have substantially greater antioxidant properties, that is, greater antithickening and anticorrosion properties plus longer periods of effectiveness than heretofore known.

Hereinbefore and hereinafter, the term normal referring t0 the metal salts of the invention denotes the ratio of the number of equivalents of metal moiety to the number of equivalents of alkylphenol moiety is about I, that is, the metal ratio of about 1. In contrast, the term overbased means that the ratio of the number of equivalents of metal is greater than 1, that is, the metal ratio if greater than 1.

SUMMARY OF INVENTION DETAILED DESCRIPTION OF THE INVENTION Specifically, the sulfurized normal or overbased Group 11 metal nitrated alkylphenolate reaction product having a sulfur content between about 0.1 and 10 wt. 7:, and nitrogen content between about 0.3 and 6 wt. and a metal ratio between 1 and 3 is assigned the hypothetical formula:

where R is alkyl of from 6 to 30 carbons, preferably from 9 to 15 carbons, x is an average integer of from 1 to 4, y is an average integer of from 0 to 10, m is an average integer from 0 to 2, M is a Group II metal cation and Z is an anion selected from the group consisting of O ,-(OH) ,-(-O-A-OR) where A is alkanediyl of from 1 to 6 carbons and R is alkyl of from 1 to 25 carbons. It is to be noted x, y and m are defined as average integers and the foregoing formula is only set forth as a hypothetical representation since the sulfurized normal or overbased Group 11 metal nitrated alkylphenolate is in essence a complex mixture of substances including mono and polysulfides which can be accurately only defined in terms of process. In any case, the nitrated group is thought to be principally amino and the R group is believed to be primarily in the para position with the nitrated group and sulfer links principally in the ortho position. Further, there is probably also a significant amount of covalent character to the Group 11 metal oxygen bond. It is to be noted that the sulfurnitrogen contents of the sulfurized Group 11 metal nitrated alkylphenolates are respectively between about 1 and 10 wt. and between about 0.3 and 6 wt. and the metal ratio is between about 1 and 3.

In the first stage of the product defining process, an alkylphenol characterized by the formula:

where R is as heretofore defined, is contacted with an nitrating agent selected from the group consisting of dilute aqueous nitric acid (1-50 wt. N0 N 0 N 0 or mixtures of alkali or alkaline earth metal nitrates and mineral acids at a temperature of between about 0and 100C., the preferred range depending on 0 the particularly nitrating agent employed, utilizing a mole ratio of alkylphenol to nitrating agent of between about 1:1 and 1:4, to form nitroalkylphenol characterized by the formula:

where R is an heretofore defined. The reaction is normally conducted for a period of between about 1 and 7 hours. Specific examples of the metal nitrate contemplated herein are sodium nitrate, potassium nitrate,

lithium nitrate, ammonium nitrate, barium nitrate, calcarbons and R is alkyl of from 1 to 25 carbons at a temperature of between about 80-220C., preferably between about 160-200C., utilizing a mole ratio of metal reagent to nitrated alkylphenol of between 1:2 and 3:1 to form normal or overbased Group 11 metal nitrated alkylphenolates characterized by the formula:

..0 M'mMZ where R, M, Z and m are as heretofore defined.

Under preferred conditions, an inert diluent is employed, for example, a hydrocarbon lubricating oil of an SUS viscosity of between about 100 and 500 at 100F. The diluent amounts utilized are normally between about 10 and 90 wt. Under further preferred conditions, the reaction is conducted in an inert gas atmosphere, e.g., nitrogen in order to prevent air oxidation of the intermediate product. The reaction is normally conducted for a period of between about 0.5 and 3 hours.

Specific examples of the metal reagents in the second stage are calcium oxide, calcium hydroxide, calcium methoxyethoxide, magnesium oxide, magnesium hydroxide, magnesium ethoxyethoxide, barium oxide, barium hydroxide, barium methoxypropoxide, zinc hydroxide, and zinc mcthoxyethoxide.

In stage 3, the Group 11 metal salt of the nitrated alkylphenol, preferably carried over in the diluent of Stage 2, is contacted with sulfur at a temperature between about 120 and 230C, preferably between l75and 210C, utilizing a mole ratio of metal salt to sulfur of between about 1:1 and 1:10. The reaction is normally conducted for a period of between about 1 and 25 hours. Under preferred conditions, the reaction is conducted in an inert gas atmosphere (e.g. nitrogen), most preferably with inert gas blowing to remove volatile sulfur by-products. The sulfurization is continued until a product if formed having a sulfur content between about 0.1 and 10 wt.

Specific examples of the sulfurized normal and overbased Group ll metal nitrated alkylphenolate product based on the formula:

are where R is 4-octyl, is 1, is 0. m is 0 and M is calcium; R is 4-dodecyl, x is l, y is l. m is 0 and M is barium; R is 4-eicosyl, is 3 and y is 5, m is (land M is zinc; R is 2,4-didecyl, .r is 2, y is 3, m is 0 and M is calcium; R is 4-decyl, x is 1, y is 1, m is 2, M is calcium and Z is (methoxyethoxide-)-; and R is 4-pentadecyl, .r is 2, y is 3, m is 4, M is barium and Z is (OH) It is to be noted that x, y and m are defined as average integers.

1n the lubricating oil compositions of the invention, the sulfurized Group 11 metal nitrated alkylphenol salt additive may range anywhere from about 0.1 to about 50 wt. Compositions containing the higher concentrations, e.g., between about 10 and 50 wt. are normally classified as the lube oil concentrates, the concentrate form of the lubricating oil compositions being prepared in the interests of minimal weight and volume in storage and transportation. In the finished lubricating oil compositions, suitable for automotive use, the concentrated forms are diluted with additional lubricating oil to give a sulfurized phenolate additive content of between about 0.1 and 10 wt. preferably between 5 and 8 wt. 76, and preferably a lube oil component SUS viscosity at 100F. of between about 600 and 900.

In the concentrate and finished lubricating oil compositions, other additives may be included. These other additives may be supplementary sludge dispersants (e.g. petroleum sulfonates), supplementary antioxidants, silver corrosion inhibitors, viscosity index improvers, oiliness agents and antifoam agents. Exactly what additives are included in the finished oil and the particular amounts thereof will, of course, depend on the particular use and conditions desired by the fin ished oil product.

One particular suitable supplementary additive for use in the concentrate and finished lubricating oil compositions contemplated herein is the ethoxylated derivative of inorganic phosphorus acid free, steam hydrolyzed polyalkene P 5 reaction product prepared by first reacting a polyalkene (e.g. polybutene) of a molecular weight of between about 800 and 2,500, wherein the reaction mixtures constitute between about 5 and 40 wt. 7: P 5 in a non oxidizing atmosphere, e.g., nitrogen, followed by hydrolyzing the resultant product by contracting with steam at a temperature between about land 260C, the steam treatment of the P S -polyalkene reaction product results in hydrolysis to form inorganic phosphorus acids in addition to the hydrolyzed organic product.

The inorganic phosphorus acids are removed from the hydrolyzed product priot to reaction with alkylene oxide by a standard procedure such as those disclosed in US. Pat. No. 2,951,835 and 2,987,512 wherein removal is effected by contact with synthetic hydrous alkaline earth metal silicates and synthetic hydrous alkali metal silicates respectively. Inorganic phosphorus acids also can be removed by extraction with anhydrous methanol is disclosed in U.S. Pat. No. 3,135,729. The steam hydrolyzed inorganic phosphorus acid product is then contacted with ethylene oxide at a temperature between about 60 and 145C. under a pressure ranging from about 0 to 50 psig utilizing a mole ratio of ethylene oxide to hydrolyzed hydrocarbon-P 8 reaction product of between about 1:1 and 4:1, preferably about 1.1:] and :1. Excess ethylene oxide is removed after completion of the reaction by blowing the reaction mixture at an elevated temperature, generally with an inert gas such as nitrogen.

The foregoing reactions are conducted in the presence of a hydrocarbon lubricating oil of the type described in connection with the sulfurized alkylphenolates and lubricant compositions thereof. The lubricating oil normally constitutes between about and 80 wt. 7t of the reaction mixture. The introduction of the hydrocarbon lubricating oil normally takes place subsequent to the steam hydrolysis. The ethoxylated derivative on an oil free basis normally has a sulfur content of between about 2 to 5 wt. 92 and a phosphorus content between about 4 and 6 wt. /z.

Specific examples of the ethoxylated derivative of the inorganic phosphorus acid free, steam hydrolyzed, polyalkene-P S reaction produce are ethoxylated steam hydrolyzed polysiobutene (1,200 m.w.)P S reaction product; ethoxylated steam hydrolyzed polybutene (l,5OOm.w.)P S reaction product; ethoxylated steam hydrolyzed polypropylene (800 m.w.)P S reaction product; ethoxylated steam hydrolyzed polyisobutylene (2000 m.w.)P S reaction product where the ethylene oxide component and the reaction product component are present in a mole ratio of 1:1.

Suitable base oils useful in the compositions of the invention as well as in the preparation of the sulfurized Group 11 metal nitrated alkylphenolate and the supplementary steam hydrolyzed polyalkene-BS, reaction product can include a wide variety of hydrocarbon lubricating oils such as naphthenic oil, paraffinic oil and mixtures thereof or other hydrocarbon lubricating oils, e,g., lubricating oil derived from coal products, synthetic oils, e.g., alkylene polymers such as polypropylene and polyisobutylene of a modecular weight of between about 250 and 2,500. Advantageously, lubricating oils having an SUS viscosity at 100F. between about and 2000, preferably between about 600 and 900, are employed.

The following examples further illustrate the additive and lubricant compositions of the invention but are not to be construed as limitations thereof.

EXAMPLE 1 This example illustrates the sulfurized Group 11 metal nitrated alkylphenolate additive and the product defining method of preparation.

State 1 To a five liter reactor there was charged 4-C alkylphenol in an amount of 1,120 grams (4 moles). Two liters of 10 wt. aqueous nitric acid were added to the charged alkylphenol at a temperature of about 31C. over a 4 hour period and the mixture was then stirred at about 31C. for an additional 2 hour period. The aqueous phase of the reaction mixture was then drained off and the organic phase was washed free of nitric acid and dried over anhydrous sodium sulfate. The dried product weighed 1,128 grams. Infrared spectroscopy and elemental analysis of the product indicated it to be 60 wt. of a 2-nitro-4-C, -alkylphenol and 40 wt. 7r 4-C alkylphenol.

Stage 2 To a mixture of 326 grams (1 mole) of the nitroalkylphenol prepared in Stage 1, and 330 grams of naphthenic oil of an SUS viscosity of about at 100F. there was charged 225 grams of about 8.5 wt. solution of calcium methoxyethoxide in methoxyethanol at 166C. over a period of 1 hour with stirring. Upon completion of the addition of the calcium reagent the methoxyethanol solvent was stripped off leaving 674 grams of an approximately 50 wt. 7! lube oil solution of normal calcium 2-nitro-4-C alkylphenolate characterized by the formula:

C allcyl-@ 0 Ca Stage 3 To 674 grams of the calcium nitrated alkylphenolate containing lube oil product of Stage 2, there was charged 32 grams (1 mole) of sulfur over a 1 hour period at l2ll8lC. while simultaneously blowing the reaction mixture with nitrogen at 500 cc./min. At the end of the addition period the temperature was maintained with nitrogen blowing at 174l 82C. for an additional 4 hour period. The reaction product was filtered and the product yield was 594 grams. The product was characterized by infrared and elemental analysis as a lubricating oil concentrate containing about 50 wt. of a sulfurized normal calcium salt of a 2- nitrated-4-C, alkylphenol, said concentrate having an analysis of 1.24 wt. "/1 nitrogen, 2.8 wt. calcium, 2.5 wt. 7t sulfur, a Total Base Number of 1 l2 and a metal ratio of 1.

EXAMPLE 11 This example illustrates the lubricant compositions of the invention and further illustrates the outstanding antioxidant properties of the sulfurized phenolate additives of the invention as well as their dispersant properties.

Two formulations were prepared. Formulation A, representative of the lube oil compositions of the invention, and Comparative Formulation B. In Formulation A, the sulfurized normal calcium nitrated C alkylphenol salt prepared in Example 1 was employed. Comparative Formulation B was prepared in accordance with Example l with the exception that the nitrating step was deleted. The comparative additive was approximately a 50 wt. oil concentrate of the sulfurized normal calcium 4-C -alkylphenolate, said concentrate having a calcium content of about 3.0 wt. 7a, a sulfur content of about 3.0 wt. and a metal ratio of 1.

Formulations A and B were subjected to the well known Union Pacific Oxidation Test which is described as follows:

Five liters of oxygen per hour were bubbled through sulfur content of between about 0.1 and 10 wt. and a nitrogen content of between about 0.3 and 6 wt. comprising:

a. contacting an alkylphenol of the formula:

where R is an alkyl group of from 6 to 30 carbons with a nitrating agent selected from the group consisting of aqueous nitric acid, N N 0 N 0 N 0 or mixtures of alkali or alkaline earth metal nitrates and mineral 300 mls. of test oil at 141C. in the presence of steel backed copper-lead catalyst for a period of 144 hours. At the end of this period the test oil is analyzed. In the tests, the greater (1 the catalyst weight loss, (2 the percent viscosity increase and (3 the amount of copper, iron and lead in the used oil, the poorer the oxidation inhibiting properties of the sulfurized phenolate additive.

The composition of test Formulations A and B and test results in the UFO Test are reported below in Table I:

"/1 Viscosity Increase 18. Cu ppm in used oil 3 Fe ppm in used oil 3 3 Pb ppm in used oil 5 600 Wt. Loss of Catalyst Specimen, mg. 2.7 372 A 44:66 weight ratio oil to ethoxylated derivative of inorganic phosphorus acid free. steam hydrolyzed polyhutenc 1200 m.w,)-P S reaction product wherein the derivative was formed using a 1:1 mole ratio of ethylene oxide to reaction product.

Mixture of paraffinie and naphthenic base oils of varying viscosities.

In addition to the above oxidation test Formulations A and B were subjected to a railway diesel lube oil screening test and the detergency performance of representative Formulation A was found substantially superior to that of comparative Formulation B.

As can be seen from the foregoing, the sulfurized normal calcium nitrated alkylphenolate of representative Formulation A is many times more effective as an antioxidant than the closely analogous sulfurized normal calcium alkylphenoalte of comparative Formulation B. In addition Formulation A is superior to detergency.

We claim:

I. A sulfurized Group II metal nitrated alkylphenolate having a metal ratio of between about 1 and 3, a

where R is as heretofore defined,

b. contacting said nitroalkylphenol with a Group 11 metal reagent selected from the group consisting of 30 MO, Won)... and M-(-O-AOR')2 where M is where R and M are as heretofore defined and Z is an anion selected from the group consisting of 0 +OH) and -(-O-AOR) where A and R are as heretofore defined,

c. contacting said Group 11 metal salt with sulfur at a temperature between about 120 and 230C. utilizing a mole ratio of said metal salt to said sulfur of between about 1:1 and 1:10 to form said sulfurized Group 11 metal nitrated alkylphenolate.

2. A product in accordance with claim I wherein said metal ratio is about 1 and said Group 11 metal is calclum.

3. A product in accordance with claim 1 wherein said metal ratio is about 1, said Group 11 metal is calcium,

) said nitrating agent is nitric acid, said alkylphenol is C alkylphenol, said step b is conducted in the presence of a hydrocarbon lubricating oil, said Group 11 metal reagent is calcium methoxyethoxide, and said steps b and c are conducted in the presence of an inert gas.

4. A lubricating oil composition containing between about and 99.9 wt. 7! of a hydrocarbon lubricating oil and between about 0.1 and 50 wt. of a sulfurized Group 11 metal nitrated alkylphenol having a metal ratio of between about 1 and 2, a sulfur content of between about 0.1 and 10 wt. 7( and a nitrogen content between about 0.3 and 6 wt. prepared by the method:

a. contacting an alkylphenol of the formula:

where R is an alkyl group of from 6 to 30 carbons with a nitrating agent selected from the group consisting of aqueous nitric acid, N N 0,, N 0 N or mixtures of alkali or alkaline earth metal or nitrates and mineral acid at a temperature between about 0 and 100C. utilizing a mole ratio of alkylphenol to nitrating agent of between about 1:1 and 1:4 to form nitroalkylphenol characterized by the formula:

where R is as heretofore defined,

b. contacting said nitroalkylphenol with a Group [I metal reagent selected from the group consisting of MO, M(OH) and M-(-OAOR') where M is a Group 11 metal, A is alkanediyl of from 1 to 6 car bons and R is alkyl of from 1 to 25 carbons at a temperature between about 80 and 200C. to form a Group 11 metal salt characterized by the formula:

where R and M are as heretofore defined and Z is an anion selected from the group consisting of 0 c. contacting said Group 11 metal salt with sulfur at a temperature between about 120 and 230C. utilizing a mole ratio of said metal salt to said sulfur of between about 1:1 and 1:10 to form said sulfurized Group 11 metal nitrated alkylphenolate.

S. A lubricating oil composition in accordance with claim 4 wherein said Group ll metal is calcium and said metal ratio is about 1.

6. A lubricating oil composition in accordance with claim 4 wherein said sulfurized Group ll metal nitrated alkylphenolate is present in an amount of between about 0.1 and 10 wt. 70, said Group 11 metal is calcium and said metal ratio is about 1.

7. A lubricating oil composition in accordance with claim 4 wherein said sulfurized Group 11 metal nitrated alkylphenolate is present in an amount of between about 0.1 and 10 wt. said metal ratio is about 1, said Group II metal is calcium, said calcium reagent is calcium methoxyethoxide, said alkylphenol is C alkylphenol, and said step b is conducted in the presence of between about 10 and wt. hydrocarbon lubricating oil of an SUS viscosity of between about and 500 at 100F., and said steps b and c are conducted in the presence of an inert gas. 

1. A SULFURIZED GROUP 11 METAL NITRATED ALKYLPHENOLATE HAVING A METAL RATIO OF BETWEEN ABOUT 1 AND 3, A SULFUR CONTENT OF BETWEEN ABOUT 3,1 AND 10 WT. % AND A NITROGEN CONTENT OF BETWEEN ABOUT 0.3 AND 6 WT. % COMPRISING: A. CONTACTING AN ALKYLPHENOL OF THE FORMULA:
 2. A product in accordance with claim 1 wherein said metal ratio is about 1 and said Group II metal is calcium.
 3. A product in accordance with claim 1 wherein said metal ratio is about 1, said Group II metal is calcium, said nitrating agent is nitric acid, said alkylphenol is C12 alkylphenol, said step b is conducteD in the presence of a hydrocarbon lubricating oil, said Group II metal reagent is calcium methoxyethoxide, and said steps b and c are conducted in the presence of an inert gas.
 4. A lubricating oil composition containing between about 50 and 99.9 wt. % of a hydrocarbon lubricating oil and between about 0.1 and 50 wt. % of a sulfurized Group II metal nitrated alkylphenol having a metal ratio of between about 1 and 2, a sulfur content of between about 0.1 and 10 wt. % and a nitrogen content between about 0.3 and 6 wt. % prepared by the method: a. contacting an alkylphenol of the formula:
 5. A lubricating oil composition in accordance with claim 4 wherein said Group II metal is calcium and said metal ratio is about
 1. 6. A lubricating oil composition in accordance with claim 4 wherein said sulfurized Group II metal nitrated alkylphenolate is present in an amount of between about 0.1 and 10 wt. %, said Group II metal is calcium and said metal ratio is about
 1. 7. A lubricating oil composition in accordance with claim 4 wherein said sulfurized Group II metal nitrated alkylphenolate is present in an amount of between about 0.1 and 10 wt. %, said metal ratio is about 1, said Group II metal is calcium, said calcium reagent is calcium methoxyethoxide, said alkylphenol is C12 alkylphenol, and said step b is conducted in the presence of between about 10 and 90 wt. % hydrocarbon lubricating oil of an SUS viscosity of between about 100 and 500 at 100*F., and said steps b and c are conducted in the presence of an inert gas. 